This invention relates to alkaline detergent compositions comprising a unique combination of water soluble non-ionic surfactants and anionic detergents together with other water soluble surfactants, i.e. amine oxides or amides, and at least one builder salt in an alkaline aqueous solution. More specifically, this invention is directed to a water soluble alkaline detergent particularly useful in cleaning various substrates by first treating the substrate with dilute acidic solutions of detergents and subsequently washing the acidic treated surface with an alkaline detergent comprising an aqueous solution of a mixture of an alkoxylated non-ionic surfactant and anionic detergents with water soluble amine oxides or amides and at least one builder selected from the group consisting of inorganic metal salts and polycarboxylic acid metal salts.
The detergent compositions of this invention are specifically adapted for cleaning various surfaces including brick, wood or metal substrates such as homes, buildings, cars, trucks, railroad cars and the like, and are particularly useful in spray equipment. More specifically, this invention is directed to novel detergent compositions and the method of using said compositions for performing various cleaning operations on different substrates included painted surfaces and are particularly useful for cleaning and restoring the surfaces where soil is heavy and frequently combined with oily or greasy materials. Moreover, substrates which are heavily weathered and highly oxidized have soil embedded in the paint and therefore, are even more difficult to clean. It is generally accepted that most surfaces containing greasy materials or the like may be cleaned by the use of acidic solutions. Acid solutions alone, however, were found not to be totally effective without deleteriously effecting the surface. Further, where alkaline cleaners have been used in place of the acid cleaners, such alkaline cleaners were not particularly outstanding with respect to soiled surfaces containing oxides embedded in the paint and therefore were not capable of restoring the surfaces to their original or near original condition.
In accordance with this invention, the method comprises the use of acidic detergent solutions followed sequentially with an alkaline wash comprising a unique mixture of an alkoxylated non-ionic surfactant, and an anionic detergent coupled with an amine oxide and/or amide in combination with builder salts such as the inorganic metal salts. The amine oxides or amides are added to the alkaline detergent for various reasons including, for example, to control the frothing action which prevents evaporation of water and therefore allows the detergent to remain on the surface, e.g. vertical surfaces at increased concentrations to obtain improved cleansing action. The detergent compositions of this invention are preferrably sprayed onto the substrate at increased pressures to dissolve any organic materials and effectively penetrate and remove the dirt embedded in the surface.
The use of either acidic or alkaline detergents as cleaning fluids with spray equipment is generally known. For example, U.S. Pat. No. 3,709,838 discloses a detergent containing ethanol amine salts of sulfonic acid in combination with non-ionic surfactants. U.S. Pat. No. 3,826,759 discloses a non-foaming detergent comprising a combination of non-ionic and anionic detergents with inorganic builder salts. U.S. Pat. No. 4,040,989 discloses a liquid detergent containing anionic detergents such as the sulfonates in combination with a non-ionic detergent with an alkanoic acid amide. In comparison to the teachings of the prior art, however, the instant invention is directed to a synergistic combination of certain water soluble non-ionic surfactants and anionic detergents in combination with amine oxides or alkanolamides with inorganic and organic builder salts.
Accordingly, it is an object of this invention to improve the technique for cleaning badly weathered surfaces with particular detergents. It is another object of this invention to provide a unique combination of detergents with surface active agents and builder salts capable of being used in high pressure spray equipment. It is a further object of this invention to provide a unique composition particularly useful in spray equipment for cleaning and/or degreasing various substrates at various temperatures and pressures. It is a further object of this invention to provide a process wherein the substrate is initially treated with an acidic solution of acid stable detergents and subsequently washing with a water soluble alkaline detergent in pressure equipment to restore and clean the surface of the substrate.
These and other objects will become apparent from a further more detailed description of the invention as follows: